Native Power Monitoring for Proxmox Nodes in Home Assistant (via MQTT)

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Complete Guide: Native Power Monitoring for Proxmox Nodes in Home Assistant (via MQTT)

This guide walks through setting up zero-maintenance, native CPU power monitoring for non-enterprise Proxmox nodes (like Intel NUCs, Dell OptiPlex MFFs, or custom builds).

It uses turbostat to pull accurate CPU package wattage, wraps it in an MQTT Auto-Discovery payload so Home Assistant automatically recognizes it as a device, and includes self-logging for easy troubleshooting.

Prerequisites

• A Proxmox VE node.
• An MQTT broker running on your network (like the Mosquitto Add-on in Home Assistant).
• Your MQTT IP address, username, and password.

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Step 1: Prepare the Proxmox Node

Out of the box, Proxmox looks for a paid Enterprise repository. We need to disable this to install our required packages.

1. In the Proxmox Web GUI, select your node on the left.
2. Go to Updates > Repositories.
3. Highlight the enterprise.proxmox.com repositories and click Disable. (You can also add the No-Subscription repository here to keep getting free updates).

Open your Proxmox node's shell and install the CPU tools and MQTT client:

apt update && apt install linux-cpupower mosquitto-clients -y

Step 2: Create a Secure Secrets File

Never hardcode passwords into executable scripts. We will create a hidden file restricted only to the root user.

Create the secrets file:

nano /usr/local/bin/.mqtt_secrets

Paste in your network details:

MQTT_BROKER="192.168.X.X"   # Replace with your MQTT IP
MQTT_USER="your_mqtt_user"  # Replace with your MQTT username
MQTT_PASS="your_mqtt_pass"  # Replace with your MQTT password

1. Save and exit (Ctrl+O, Enter, Ctrl+X).

Lock down the file permissions:

chmod 600 /usr/local/bin/.mqtt_secrets

Step 3: Create the Auto-Discovery Script

This script dynamically grabs the node's hostname, builds a Home Assistant Auto-Discovery JSON payload, extracts the wattage, pushes the data, and logs any errors.

1. Create the script:

nano /usr/local/bin/report_power.sh

Paste the following code:

#!/bin/bash

# Define our error log
LOG_FILE="/var/log/proxmox_power.log"

# Load variables from the secrets file
source /usr/local/bin/.mqtt_secrets

# Dynamically grab the hostname
NODE_NAME=$(hostname)
STATE_TOPIC="proxmox/${NODE_NAME}/cpu_power"
CONFIG_TOPIC="homeassistant/sensor/proxmox_${NODE_NAME}/cpu_power/config"

# Extract PkgWatt using the absolute path for turbostat
WATTAGE=$(/usr/sbin/turbostat --quiet --Summary --show PkgWatt -n 1 2>>"$LOG_FILE" | awk 'NR==2 {print $1}')

# Build the JSON Auto-Discovery Payload
CONFIG_PAYLOAD=$(cat <<EOF
{
  "name": "CPU Power",
  "object_id": "proxmox_${NODE_NAME}_cpu_power",
  "unique_id": "proxmox_${NODE_NAME}_cpu_power",
  "state_topic": "${STATE_TOPIC}",
  "unit_of_measurement": "W",
  "device_class": "power",
  "state_class": "measurement",
  "icon": "mdi:cpu-64-bit",
  "device": {
    "identifiers": ["proxmox_${NODE_NAME}"],
    "name": "Proxmox Node (${NODE_NAME})",
    "manufacturer": "Proxmox",
    "model": "Compute Node"
  }
}
EOF
)

# Push to MQTT only if the wattage is a valid number
if [[ $WATTAGE =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
    # 1. Send Config (Retained)
    mosquitto_pub -h "$MQTT_BROKER" -u "$MQTT_USER" -P "$MQTT_PASS" -t "$CONFIG_TOPIC" -m "$CONFIG_PAYLOAD" -r 2>>"$LOG_FILE"

    # 2. Send State
    mosquitto_pub -h "$MQTT_BROKER" -u "$MQTT_USER" -P "$MQTT_PASS" -t "$STATE_TOPIC" -m "$WATTAGE" 2>>"$LOG_FILE"

    # Log network errors
    if [ $? -ne 0 ]; then
        echo "$(date '+%Y-%m-%d %H:%M:%S') - ERROR: Failed to connect to MQTT Broker at $MQTT_BROKER" >> "$LOG_FILE"
    fi
else
    # Log extraction errors
    echo "$(date '+%Y-%m-%d %H:%M:%S') - ERROR: Invalid wattage reading. Got: '$WATTAGE'" >> "$LOG_FILE"
fi

2. Save and exit (Ctrl+O, Enter, Ctrl+X).

Crucial: Make the script executable:Bash

chmod +x /usr/local/bin/report_power.sh

Step 4: Automate with Cron

Tell Proxmox to run this silently in the background every 60 seconds.

Open your cron editor:

crontab -e

1. Select 1 for Nano
2. Add this line to the very bottom:

* * * * * /usr/local/bin/report_power.sh

1. Save and exit. The script is now running!(Note: If it ever fails, it will generate an error log at /var/log/proxmox_power.log. If that file doesn't exist, it means the script is running flawlessly.)
2. you can read the contents by
   'cat /var/log/proxmox_power.log'

cat /var/log/proxmox_power.log

Step 5: Limit Log size

1. create a logrotate rule

nano /etc/logrotate.d/proxmox_power

2. paste the following

/var/log/proxmox_power.log {
    size 5M
    rotate 2
    missingok
    notifempty
    compress
    copytruncate
}

3. Save and exit (Ctrl+O, Enter, Ctrl+X).

Step 6: Configure Home Assistant

Because we used an MQTT Auto-Discovery payload, there is no YAML to configure!

1. In Home Assistant, go to Settings > Devices & Services > MQTT > Devices.
2. You will see a new device named Proxmox Node (your-hostname) with a live CPU Power sensor reporting in Watts (W).
3. Optional (Energy Dashboard Integration): * Watts (Power) cannot be added to the Energy Dashboard. You must convert it to kWh (Energy).
   • Go to Settings > Devices & Services > Helpers.
   • Click + Create Helper and choose Integration - Riemann sum integral sensor.
   • Select your new Proxmox CPU Power sensor as the input.
   • Important: Set Integration Method to Left (required for spiky electrical loads). Set precision to 2, prefix to k, and time unit to h.
   • You can now add this new Energy entity to your Home Assistant Energy Dashboard!